While the present invention has application to internal combustion engines used for various purposes, the following description will relate the engine primarily to an outboard motor. In conjunction with an outboard motor, the throttle push-pull cable actuates not only the butterfly valve in the carburetor(s) but is also used to adjust the timing of the spark ignition system. Since the timing is not advanced uniformly over the throttle range of the engine, but in fact is held constant over a large part of the range, the motion imparted to the timing device is presently derived from a spring loaded, lost motion system of levers. The spring loading detracts from durability and requires more operating force. In order to get the desired motion without a spring load, a cam can be used. It is difficult to accommodate a large cam inside the motor cover. In many outboard motors the timing lever and the throttle lever are desireably on pivot axes 90.degree. apart which raises problems in transferring motion from the cam slot to the throttle. It is desirable to both reduce the space required for the apparatus and to also provide a more reliable cam and follower arrangement than found in the art.
Attention is directed to U.S. Pat. Nos. 1,611,054, 2,635,595, 3,734,069 and British Pat. No. 975,079. These patents do not teach the present linkage.